Cell Phones OFF on airplanes?

Have you ever wondered "why do i have to turn my phone off, on a stupid plane?" The answer is just BECAUSE. I watch mythbusters anytime it is on. It is one of my favorite shows to watch besides Rob and Big, and Dirty Jobs. The mythbusters tried all they could to mess up the instruments on a plane with different cell phone waves be amplified and had no results what so ever. So why do we have to turn our cell phones of on a plane? The answer came at the end of the episode. The reason is, there is so many new cell phones that do come out every year that they dont want to take the risk. They run on a different frequency and waves. Interesting..not really but it does make sense.